There’s not much that draws a great white shark to shore better than a group of seals.

In recent years, a large number of seals has been scattered across the coast of Cape Cod, officials from the Cape Cod National Seashore said. And this year, Eastham has seen an unusually high density of the animals since the summer began, putting worst-case shark scenarios into the minds of surfers and beachgoers.

Brian Voke, a Boston lawyer who has a home in Eastham, has seen groups of 50 or 60 seals and worries about safety when he goes surfing with his 12-year-old son.

Head of the Meadow Beach in Truro, near the tip of the Cape, is often home to groups of 400 or 500 seals
. Farther south, near Monomoy Beach, 10,000 seals can sometimes be seen at once, said Jason Taylor, the chief of natural resources for the National Seashore.

And as one would expect, the seals have attracted ocean visitors. On Sept. 15, a shark attacked and ate a seal off of Eastham.

“The notion that some child is going to be eaten is unnerving,” said Voke. He said he might have to tell his son they can no longer ride the waves.

“There have been occasions when surfers have been eaten,” said Leslie Reynolds, chief ranger for the National Seashore. But, she explained, in most attacks sharks take one bite and spit it out, as they desire seals and not people.

Reynolds said to stay safe, “don’t isolate yourself and make yourself an easy target.”